充电桩外壳用什么改性PP？它一边长期挂在室外日晒雨淋，一边内部电气密集发热，还要同时满足户外耐候、抗 UV、阻燃 V-0、高强度四件事。这篇把工况六维、选型判据表、验证顺序与换料风险清单讲清，并说明哪三种情况这个件不该用改性PP。
"你们这个充电桩外壳，外面的料能不能再耐晒一点，里面的阻燃又别掉？"
这是我在展会上被问得最多的一类问题。问的人往往已经试过一两家料，反馈是：户外晒了一阵子就发白变脆，或者阻燃单子报的是 V-0，可整机安规那一关又卡住了。
把这句话翻成工况就是——充电桩外壳是个"一边长期挂在室外挨晒、一边壳里电气密集自己还发热"的件。它最真实的失效现场就两个：户外晒裂、褪色，以及阻燃和耐候两头顾不上。这篇把这件事讲透。
一、开篇痛点：这个件最常倒在哪两件事上
先把痛点钉死。充电桩外壳的失效，公开资料里反复出现两类：
第一类是户外老化失效。桩体外壳长期在紫外、湿热、冷热循环下服役，时间一长表面粉化、色泽发灰、甚至变脆开裂。很多项目到了现场一两年就开始被投诉"外壳看着旧了、一磕就掉渣"。
第二类是阻燃与耐候顾此失彼。只盯阻燃的料，户外扛不住；只盯耐候的料，过不了安规。更麻烦的是，有些料 UL94 V-0 报告是有的，可整机测试时内部电弧或过热一引燃，桩体就过不了更贴近工况的那一关。
所以选型的第一句话不该是"用哪种料"，而是"这个件四件事里，哪一件允许先退一步"。 这四件事是：户外耐候、抗 UV、阻燃 V-0、高强度。下面先把工况摊开。
二、工况六维拆解：四件事同时压过来
充电桩外壳的工况，按六个维度拆开看，把数报齐，方向基本就定了。
| 维度 | 充电桩外壳的实际工况 | 对材料的要求 |
|---|
| 温度 | 户外夏季暴晒壳体表面局部可到 70-85℃；内部电气密集发热使局部再升一截；冬季可到 −30℃ 以下 | 既要耐外部热老化，又要扛内部温升 |
| 载荷 | 固定安装，承受自重、风载、安装扭矩与防护密封压；偶然外力撞击概率低 | 刚性、尺寸稳定为主，不强调冲击 |
| 介质 | 雨水、融雪盐雾、臭氧、紫外、周边油污飞溅 | 耐候 + 耐化学 |
| 寿命 | 户外服役常按 10-15 年设计，紫外累计辐照与热循环叠加 | 长期老化后强度与外观不塌 |
| 外观 | 长期户外可见件，色差与粉化直接被用户看见 | 氙灯老化后 ΔE≤3.0，表面不粉化 |
| 合规 | 阻燃 UL94 V-0；无卤限值；灼热丝；整机安规 | 阻燃 + 灼热丝 + 无卤环保三道线 |
六个维度里，温度、寿命、外观、合规这四维都给了硬数字，它们才是这道选题的骨架。
一个内行细节：户外件的老化不是"晒褪色"一件事。行业通行做法是加一道"UV + 热老化"的联合试验——要求在 500-1000 h 之后，件的性能还不能往下掉。只看氙灯色差、不看过联合老化的料，往往现场一两年就出问题。这一点，后面选型判据表里会专门列出来。
三、材料路线对比：三条路并列，不做谁更好
改性PP 解决这个件，行业上能走三条路线。把它们并排看，比单线展开更清楚。
| 路线 | 同时拿到什么 | 代价 / 短板 |
|---|
| 耐候体系（UVA + HALS 配合） | 抗 UV、抗老化、外观长期稳定 | 不解决阻燃，过不了 V-0 |
| 阻燃体系（无卤膨胀型为主） | 过 UL94 V-0、灼热丝表现好 | 单独用，户外长期晒会褪色变脆 |
| 耐候 + 阻燃双体系 | 户外耐候、抗 UV、阻燃 V-0、高强度四件事同时满足 | 阻燃剂加量到 25-30% 档，力学必然掉一截，靠矿物或玻纤填充保刚性；成本最高 |
三条路没有"谁更好"的结论。固定户外、内部带电、还看得见的件，基本只能落第三条；只做户内小桩或纯结构遮罩，才可能往下两档退。
这里有一处必须讲清的结构性事实：PP 本身易燃，阻燃剂加量普遍在 25-30% 这一档——"阻燃剂加得多、力学就一定掉"是 PP 的结构性问题，不是配方水平问题。遇到"又要 V-0、又要高强度、还要便宜"的期望，先谈排序，再谈料。
敢否定一个常见做法：有人以为"阻燃过了 V-0，这个件就安全了"。这是错的。充电桩内部电气密集，真正贴近工况的是 850℃ 灼热丝接触 30 s 不引燃这一条，它比单纯过 V-0 更贴这个件的现场。只拿 V-0 一张报告去对应全部安规，是选型时最常见的疏漏。
四、★ 选型判据表：五项列，每项带验证方法
下面这张表是全篇最该收藏的部分。注意第三列"验证方法·标准号"——选型时最常卡住的不是"要看哪个指标"，而是"拿什么测、测到多少算过"。
| 指标 | 门限值 | 验证方法 · 标准号 | 常见失效 | 通行解法 |
|---|
| 氙灯老化色差 | ΔE≤3.0 | GB/T 16422.2（氙灯老化） | 褪色、失光、粉化 | 耐候体系（UVA + HALS 配合） |
| UV + 热老化后性能 | 500-1000 h 后性能不下降 | 户外件附加联合老化试验 | 长期变脆、强度塌陷 | 双体系整体设计，不分开加 |
| 阻燃等级 | UL94 V-0 | UL94 | 引燃周边、滴落引燃 | 无卤膨胀型阻燃 + 片状填料抑滴 |
| 灼热丝（内部电气密集） | 850℃ 接触 30 s 不引燃 | IEC 60695 灼热丝试验 | 内部电弧 / 过热引燃壳体 | 无卤阻燃 + 玻纤 / 矿物填充 |
| 灼热丝起燃温度 GWIT | 750 / 775℃ | IEC 60695-2-13 | — | 无卤阻燃体系 |
| 灼热丝燃烧指数 GWFI | 850 / 960℃ | IEC 60695-2-12 | — | 无卤阻燃体系 |
| 无卤量化 | 溴 <900 ppm、氯 <900 ppm、两者总和 <1500 ppm | 卤素含量测试 | 环保合规不达标 | 无卤原料与助剂体系 |
| 刚性 / 强度 | 矿物或玻纤填充保刚性 | GB/T 1040 / GB/T 9341 | 变形、塌陷、装配松 | 玻纤或矿物填充补刚性 |
文字版结论：八项里 850℃ 灼热丝与 UV + 热老化 500-1000 h 是最容易被漏掉的两项——前者贴内部电气工况，后者贴户外寿命。无卤的量化线（溴、氯各自 <900 ppm、总和 <1500 ppm）是环保合规的硬门槛，不是"看着写"。把这张表当体检单，缺一项不判合格，比整机测试打回省钱得多。
五、常见失效与根因：四个现象，四条根因
失效一：户外晒裂、变脆。 根因多数不是"料变差了"，常见有三：耐候体系只加了 UVA 没加 HALS，或阻燃剂自身光稳定性一般，或双体系没一起设计、互相消耗配方空间。先查耐候体系是不是两种活都干了，再查料，顺序反了会白换几轮。
失效二：V-0 过了，整机安规过不了。 根因是只拿了 UL94 报告，没验证 850℃ 灼热丝 30 s 不引燃。充电桩内部电气密集，这条比 V-0 更贴工况——这是这个件和纯外观件最大的分水岭。
失效三：褪色、色差明显。 根因常与颜色有关：深色件吸热更严重，热氧老化更明显；或色母本身不耐候。判定要分两步：色差先看色母与批次，粉化再看耐候体系。
失效四：无卤料力学掉太多、装配松。 根因是阻燃剂加到了 25-30% 这一档，这是 PP 的结构性代价，不是配方水平问题。敢否定一个认知：以为"加得多力学掉"是哪家供应商水平不行。 不是。要的是用矿物或玻纤填充把刚性补回来，而不是赌阻燃剂加少点。
六、验证顺序：先验什么，后验什么
这一段同行几乎没人写，但它是换料能不能省钱的关键。顺序错了，成本会在最后一步集中爆出来。
`
① 小样物理比对 拉伸 / 弯曲 / 缺口冲击 / 收缩率 / MFR + 阻燃 V-0 初筛
↓ 五项在门限内、V-0 初过，才往下走
② 耐候与灼热丝验证 氙灯老化 ΔE≤3.0；UV+热老化 500-1000 h 性能保持；
850℃ 灼热丝 30 s 不引燃；GWIT / GWFI
↓ 这一关不过，后面全部不用做
③ 短射试模 看充填是否完整、熔接线在哪、有没有浮纤、排气是否够
↓ 短射走通，才谈批量
④ 装配合规 防护等级、装配间隙、色差一致性
↓
⑤ 批量试产 + 客户端户外验证
`
文字版结论：验证顺序是 小样 → 耐候/灼热丝 → 短射 → 装配合规 → 批量。耐候和灼热丝这两关必须在短射之前过，因为它们是最可能一票否决的项；过了它们再做模具侧的事，才不会白花试模费。
七、反向诚实：这三种情况，这个件不该用改性PP
前面讲的是"怎么做"，这里讲"什么时候别做"。这一段对选型判断的价值最高。
| 出现的情况 | 为什么改性PP不合适 | 该往哪走 |
|---|
| 要求长期工作温度 150℃ 以上 | 改性PP 的耐热上限就在那条线附近，填充增强往上抬也有边界 | 换更高耐热的工程塑料或金属 |
| 要求 A 级表面 + 免喷涂 + 高阻燃 同时满足 | 免喷涂要求表面细腻少填料，高阻燃要求高填充/高阻燃剂，方向对拉 | 表面件与结构件分开设计，或换材料 |
| 要求 金属级屏蔽 / 散热功能 | PP 本性是绝缘隔热，屏蔽与导热要靠金属或专用复合 | 走金属件或导电/导热专用体系 |
规律是一致的：只要出现"两个方向相反的要求同时要"，就说明这个件不该用 PP 硬撑。 比如既要 A 级免喷涂外观、又要高阻燃高填充，这两个方向天然对拉。遇到这种情况，我们的做法是先把这条讲清楚，再谈有没有折中空间——硬接下来的单子，最后都要用返工和索赔还回去。
八、换料要动什么：一张先看再动的清单
决定试改性PP 之前，这张表建议先过一遍。客户真正的顾虑往往不是性能，是"我现在的模具和工艺要不要改"。
| 要动的项 | 需要确认什么 | 不做会怎样 |
|---|
| 模具收缩率 | 新料收缩率与原方案的差，长件上尤其敏感 | 尺寸超差，装配间隙对不上 |
| 浇口与排气 | 阻燃填充料对浇口位置、排气更敏感 | 充填不足、烧焦、熔接线弱 |
| 料温与模温 | 无卤阻燃体系热稳定性窗口不同 | 分解、表面缺陷、熔接线强度不足 |
| 干燥 | 看具体体系，阻燃填充料按需确认 | 银丝、气泡、性能波动 |
| 保压与脱模 | 收缩差异带来变形与顶白 | 变形、顶出拉伤 |
| 色差 | 户外件必须先确认色板再上机 | 批次色差、褪色争议 |
| 验证顺序 | 小样 → 耐候/灼热丝 → 短射 → 装配合规 | 风险全部压到最后一步集中爆发 |
文字版结论：换料要动的是模具、工艺、色差三块，其中最该先谈的是验证顺序。跳过小样直接试模，等于把成本提前花出去；跳过耐候/灼热丝直接批量，一次失败就是整批损失，而且户外件的问题往往要一两年才暴露。
九、一页纸汇报表（可以直接贴进 PPT）
| 场景 | 推荐路线 | 关键指标 | 验证标准 | 需先确认的条件 |
|---|
| 户外固定充电桩外壳 | 耐候 + 无卤阻燃双体系 + 玻纤/矿物填充 | ΔE≤3.0；850℃ 灼热丝 30 s 不引燃；无卤达标 | GB/T 16422.2；IEC 60695；卤素测试 | 安装环境（室内/露天）、当地最低温 |
| 高阻燃需求桩体 | 无卤阻燃增强 PP（玻纤） | UL94 V-0；GWIT 750/775℃；GWFI 850/960℃ | UL94；IEC 60695-2-13/2-12 | 内部电气密度、散热条件 |
| 长寿命户外件 | 双体系 + 联合老化验证 | UV+热老化 500-1000 h 性能不降 | 户外件附加联合老化 | 设计服役年限、颜色深浅 |
| 成本敏感小桩 | 耐候体系 + 低阻燃档（户内/遮罩类） | 耐候为主、阻燃按部件定 | GB/T 16422.2 | 是否户内、是否带电密集 |
文字版结论：这张表的作用是让技术员能把结论直接往上报，不必重新组织语言。判断标准只有一条——客户拿这张表，能不能在一次会议里把材料方向定下来。
十、这个件上最容易出问题的，往往不是料
行业内这类件最常出的早期失效，是户外晒裂变脆和"V-0 过了整机安规过不了"两类。公开资料把难点讲得很清楚：户外件的耐候不能只看氙灯色差，还要过 UV + 热老化 500-1000 h 之后性能不下降这一关；而充电桩内部电气密集，贴近工况的是 850℃ 灼热丝接触 30 s 不引燃，不是单纯一张 V-0 报告。
判据层面，行业通行的硬线是这几条：氙灯老化 ΔE≤3.0（GB/T 16422.2）；无卤量化按溴 <900 ppm、氯 <900 ppm、两者总和 <1500 ppm；灼热丝 GWIT 750/775℃、GWFI 850/960℃。同时，无卤路线要避开有卤的代价——加工受热释放卤化氢腐蚀设备模具，燃烧释放卤化氢与浓烟。
行业通行的做法是把耐候体系和无卤阻燃体系一起设计：基材选抗冲共聚 PP 打底，耐候走 UVA + HALS 配合，阻燃走无卤膨胀型并引入片状填料抑滴控收缩，刚性靠矿物或玻纤填充补回来——分开加料最容易"单项过、合起来不过"。
宁波市科隆新材料有限公司在这个件上常供的是改性聚丙烯（PP）粒子里的耐候 + 无卤阻燃双体系方向，按户外工况给到对应的基材档位与阻燃/耐候体系，主要用来解决上面说的"户外晒裂 + 阻燃过不了灼热丝"这两件事；可以配合做小样比对与试模验证，件级客户多品种小批量的需求也能接。
常见问答
问：无卤和有卤到底差在哪，为什么都推无卤？
答：不点名品牌，只讲可验证的部分。无卤的量化线是溴、氯各自 <900 ppm、总和 <1500 ppm；有卤的代价是加工受热释放卤化氢腐蚀设备模具、燃烧释放卤化氢与浓烟。对户外带电件，无卤是更稳妥的环保与安规方向。
问：阻燃剂加得多，力学掉一截，能不能靠配方补回来？
答：这是 PP 的结构性问题，不是配方水平问题。正解是靠矿物或玻纤填充把刚性补回来，同时把耐候和阻燃两套体系一起设计，而不是赌阻燃剂少加。允许哪一条退一点，比先选牌号更重要。
| 工况 | 关键判据 | 科隆常规供应 |
|---|
| 户外充电桩外壳 | ΔE≤3.0；850℃ 灼热丝 30 s；无卤达标 | 耐候 + 无卤阻燃双体系改性PP方向 |
| 高阻燃桩体 | UL94 V-0；GWIT/GWFI | 无卤阻燃增强 PP（玻纤）方向 |
| 长寿命户外件 | UV+热老化 500-1000 h 不降 | 双体系 + 联合老化验证方向 |
想提醒一句：件出问题，最常见的错法是先换料。晒裂、褪色、安规过不了——每一条的原因都不止一个。先定位，再换料；顺序反了，往往换了几轮还在原地。
最后说三句。 第一，充电桩外壳选型的第一句话是"四件事里哪一件允许先退一步"，不是"哪种料好"——户外耐候、抗 UV、阻燃 V-0、高强度，四件同时要。第二，850℃ 灼热丝和 UV + 热老化 500-1000 h，是这张选题最容易漏的两项，前者贴内部电气工况、后者贴户外寿命，都比单看 V-0 和氙灯色差更贴现场。第三，验证顺序比验证项更重要，小样 → 耐候/灼热丝 → 短射 → 装配合规，灼热丝和老化这两关必须放在试模之前。
下一篇讲免喷涂与耐划伤——那个件最怕的不是刚性不够，是外观件在户外先粉化发白。
关于我们
报价之前先聊三件事：这个件用在哪儿、要求哪几条、哪一条可以掉下来。
尤其第三件。改性 PP 的指标之间不是加法，是对拉——阻燃和增韧对拉，高流动和抗冲对拉，玻纤和尺寸稳定对拉。不排个先后，价格报不准，方案也稳不住。
What type of modified PP is used for the charging pile casing? It is exposed to long-term outdoor sunlight and rain on one side, while the internal electrical components generate concentrated heat, and it also needs to simultaneously meet four requirements: outdoor weather resistance, UV resistance, V-0 flame retardancy, and high strength. This article clarifies the six-dimensional operating conditions, the selection criteria table, the verification sequence, and the list of material replacement risks, and explains the three situations in which this part should not use modified PP.
Can the outer material of your charging pile casing be more sun-resistant, while the flame retardant inside doesn't come off?
This is the type of question I get asked the most at exhibitions. People who ask have usually tried one or two materials, and the feedback is: after being exposed outdoors for a while, it turns white and becomes brittle, or the flame-retardant data sheet says V-0, but then the whole device fails the safety compliance stage.
Translating this sentence into working conditions means——the charging pile casing is a component that 'is hung outdoors on one side for a long time under the sun, while the interior is densely packed with electrical parts that generate heat themselves.' Its most real failure scenarios are just two: cracking and fading from sun exposure outdoors, and being unable to take care of both flame retardancy and weather resistance. This article explains this matter thoroughly.
1. Opening Pain Points: What are the two things this issue most commonly fails at?
First, pin down the pain points. Failures of the charging pile casing appear repeatedly in public information in two categories:
The first type is outdoor aging failure. The pile casing has been in service for a long time under ultraviolet light, humidity and heat, and temperature cycling. Over time, the surface chalks, the color turns gray, and it may even become brittle and crack. In many projects, after one or two years on-site, complaints start to appear that 'the casing looks old and crumbles at the slightest impact.'
The second category is that flame retardancy and weather resistance can't be achieved simultaneously. If you only focus on flame-retardant materials, they can't withstand outdoor conditions; if you only focus on weather-resistant materials, they won't pass safety regulations. What's more troublesome is that some materials have a UL94 V-0 report, but during full device testing, if internal arcing or overheating ignites, the charging pile won't pass the test that is closer to real-world conditions.
So the first question when choosing a material should not be 'Which material to use,' but 'Among these four aspects of the part, which one can be compromised first?' These four aspects are: outdoor weather resistance, UV resistance, V-0 flame retardancy, and high strength. Let's first lay out the working conditions below.
2. Six-Dimensional Breakdown of Working Conditions: Four Things Hitting at the Same Time
The operating conditions of the charging pile enclosure, when broken down into six dimensions and the data compiled, basically determine the direction.
| Dimension | Actual working conditions of the charging pile casing | Requirements for the materials |
|---|
| Temperature | The surface of the shell exposed to outdoor summer sun can locally reach 70-85°C; concentrated internal electrical heat can raise the local temperature even further; in winter, it can drop below −30°C. | It needs to withstand external heat aging while also enduring internal temperature rise. |
| Load | Fixed installation, bearing self-weight, wind load, installation torque, and protective sealing pressure; low probability of accidental external impact | Primarily rigid and dimensionally stable, not emphasizing impact |
| Medium | Rainwater, melting snow salt spray, ozone, ultraviolet, surrounding oil splashes | Weather-resistant Chemical-resistant |
| Lifespan | Outdoor service is usually designed for 10-15 years, with cumulative ultraviolet radiation combined with thermal cycling. | Does not collapse in strength and appearance after long-term aging |
| Appearance | Visible parts exposed outdoors for a long time, color difference and chalking are directly seen by users | After xenon lamp aging, ΔE ≤ 3.0, surface does not chalk |
| Compliance | Flame retardant UL94 V-0; halogen-free limit; glow wire; complete machine safety regulations | Flame retardant Glow wire Halogen-free environmentally friendly three-core cable |
Among the six dimensions, temperature, lifespan, appearance, and compliance all provide concrete numbers; they are the backbone of this selection question.
An insider detail: the aging of outdoor components is not just about "fading from sunlight." The common industry practice is to add a combined "UV and heat aging" test — requiring that after 500-1000 hours, the component's performance should not decrease. Simply looking at the color difference from a xenon lamp test, without considering the material's performance under combined aging, often leads to problems in the field within a year or two. This point will be specifically listed in the selection criteria table later.
3. Comparison of material routes: three routes side by side, not judging which is better
Modified PP addresses this part, and the industry can take three routes. Placing them side by side is clearer than expanding them in a single line.
| Route | Get what at the same time | Cost / Shortcoming |
|---|
| Weathering system (UVA HALS combination) | UV resistant, anti-aging, long-term appearance stability | If the flame retardancy is not addressed, it cannot pass V-0. |
| Flame-retardant system (mainly halogen-free expandable type) | Passed UL94 V-0, performs well in the glowing wire test | Use alone, prolonged outdoor exposure will cause fading and brittleness |
| Weather-resistant flame-retardant dual system | Outdoor weather resistance, UV resistance, flame retardant V-0, high strength—all four requirements are met simultaneously | Increasing the flame retardant to 25-30% will inevitably reduce the mechanical properties, so rigidity must be maintained with mineral or glass fiber fillers; the cost is the highest. |
There is no 'which is better' conclusion among the three approaches. Fixed outdoor, internally powered, and still visible components can basically only fall to the third category; only doing small indoor posts or purely structural shielding might be able to drop down two levels.
There is a structural fact that must be made clear here: PP itself is flammable, and the amount of flame retardant added is generally in the range of 25-30%—the idea that 'adding more flame retardant will definitely reduce mechanical strength' is a structural issue of PP, not a formulation-level issue. When faced with the expectation of 'wanting V-0, high strength, and low cost' at the same time, first discuss the priorities, and then discuss the materials.
Can we challenge a common practice: some people think 'once the flame retardant passes V-0, this component is safe.' This is wrong. Inside a charging pile, the electrical components are dense, and the test closest to the actual working conditions is the 850℃ hot wire contact for 30 seconds without ignition. This is more relevant to the component's real environment than simply passing V-0. Using only a V-0 report to cover all safety regulations is the most common oversight during selection.
4. ★ Selection Criteria Table: five items listed, each with a verification method
The table below is the part of the whole article most worth saving. Pay attention to the third column 'Verification Method · Standard Number' — the most common sticking point when selecting is not 'which indicator to look at,' but 'what to measure with, and how much counts as passing.'
| Indicator | Threshold value | Verification Method · Standard Number | Common Failures | Common solution |
|---|
| Xenon lamp aging color difference | ΔE ≤ 3.0 | GB/T 16422.2 (Xenon Lamp Aging) | Fading, loss of gloss, powdering | Weathering system (UVA HALS combination) |
| Performance after UV thermal aging | Performance does not degrade after 500-1000 hours | Outdoor Component Additional Combined Aging Test | Long-term brittleness and strength collapse | Dual-system overall design, do not add separately |
| Flame retardant rating | UL94 V-0 | UL94 | Ignite surroundings, drip ignition | Halogen-free intumescent flame retardant, flake filler drip suppression |
| Incandescent filament (electrically intensive inside) | 850℃ contact for 30 s does not ignite | IEC 60695 Glow-Wire Test | Internal arc / overheated ignition casing | Halogen-free flame retardant Glass fiber / mineral filled |
| Glow wire ignition temperature GWIT | 750 / 775℃ | IEC 60695-2-13 | — | Halogen-free flame retardant system |
| Glow Wire Flammability Index GWFI | 850 / 960℃ | IEC 60695-2-12 | — | Halogen-free flame retardant system |
| halogen-free quantification | Bromine <900 ppm, Chlorine <900 ppm, Total of both <1500 ppm | Halogen Content Test | Environmental compliance not up to standard | Halogen-free raw materials and additive system |
| Rigidity / Strength | Mineral or glass fiber filled rigidity | GB/T 1040 / GB/T 9341 | Deformation, collapse, loose assembly | Glass fiber or mineral filled to enhance rigidity |
Text version conclusion: Among the eight items, the 850℃ glowing wire test and UV thermal aging for 500-1000 hours are the two most easily overlooked— the former relates to internal electrical conditions, and the latter to outdoor lifespan. The quantification line for halogen-free (bromine and chlorine each <900 ppm, total <1500 ppm) is a hard environmental compliance threshold, not something you just 'write for appearances.' Treat this table like a physical examination report: missing any item means not qualified, which saves much more money than having the whole machine test rejected.
5. Common Failures and Root Causes: Four Phenomena, Four Root Causes
Failure 1: Cracking and brittleness outdoors. The root cause is often not that the material has deteriorated; there are three common reasons: the weathering system only includes UVA without HALS, or the flame retardant itself has general photo-stability, or the dual system was not designed together and they consume each other's formulation space. First, check whether both activities in the weathering system are effective, and then check the material. If the order is reversed, you might waste several rounds.
Failure 2: V-0 passed, but the whole device cannot pass the safety regulations. The root cause is that only the UL94 report was obtained, and it was not verified that a 850℃ glow wire for 30 seconds does not ignite. The interior of the charging pile is electrically dense, and this criterion is more representative of actual working conditions than V-0 — this is the biggest dividing line between this component and purely cosmetic parts.
Failure Three: Fading, noticeable color difference. The root cause is often related to color: dark-colored parts absorb heat more severely, making thermal-oxidative aging more obvious; or the color masterbatch itself is not weather-resistant. Determination should be done in two steps: for color difference, first look at the masterbatch and batch; for powdering, then check the weather resistance system.
Failure 4: Excessive loss of mechanical properties due to halogen-free materials and loose assembly. The root cause is that the flame retardant was added at the 25-30% level. This is a structural cost of PP, not a formulation-level issue. Dare to challenge a common belief: thinking 'adding more reduces mechanical properties' is due to subpar supplier quality. It's not. What’s needed is to use mineral or glass fiber fillers to restore rigidity, rather than gambling by adding less flame retardant.
6. Verification sequence: what is a priori, what is a posteriori
Almost no one in the industry writes this section, but it is key to whether material substitution can save money. If the order is wrong, the cost will all come out in the last step.
`
① Sample Physical Comparison Tensile / Bending / Notched Impact / Shrinkage / MFR Flame Retardant V-0 Preliminary Screening
↓ Only after the five items are within the threshold and V-0 passes initially should we proceed.
② Weathering and Hot Wire Testing Xenon lamp aging ΔE≤3.0; UV heat aging 500-1000 h performance retention;
850℃ glowing wire 30 s does not ignite; GWIT / GWFI
If you don't pass this level, you don't need to do the rest.
③ Short shot mold trial Check if the filling is complete, where the weld lines are, if there are any floating fibers, and whether the venting is sufficient
↓ Only after the short test run succeeds can we talk about mass production
④ Assembly Compliance Protection level, assembly gap, color consistency
↓
⑤ Batch trial production Client-side outdoor verification
`
Text version conclusion: The verification sequence is: sample → weathering/heat filament → short shot → assembly compliance → mass production. The weathering and heat filament steps must pass before the short shot, because they are the items most likely to result in outright rejection; only after passing them should work on the mold side be done, so as not to waste the mold trial costs.
7. Reverse Honesty: In these three situations, this part should not use modified PP
Earlier we talked about 'how to do it'; here we talk about 'when not to do it.' This section is the most valuable for making selection decisions.
| The situation that occurred | Why is modified PP not suitable? | Which way should I go? |
|---|
| Requires a long-term operating temperature above 150℃ | The heat resistance limit of modified PP is around that line, and even filling and reinforcement have boundaries when pushing it higher. | Switch to higher heat-resistant engineering plastics or metals |
| Requires Class A surface, no coating, high flame retardancy, all requirements met simultaneously | Spray-free requires a fine surface with little filler, high flame retardant requires high filler/high flame retardant agent, oriented in two directions | Design the exterior parts and structural parts separately, or change the material |
| Requirements: metal-grade shielding / heat dissipation function | PP's nature is insulating and heat-resistant; shielding and thermal conductivity rely on metals or specialized composites. | Use metal parts or specialized systems for conductivity/thermal conductivity |
The rule is consistent: whenever there are 'two opposite requirements to be met at the same time,' it indicates that this part should not be forcibly made with PP. For example, if it requires both an A-level paint-free appearance and high flame retardancy with high filling, these two directions are naturally at odds. In such cases, our approach is to first make this point clear, and then discuss whether there is any room for compromise—if we push the order through forcibly, it will ultimately have to be reworked and returned through claims.
8. What to touch when changing materials: a checklist to look at before you act
Before deciding to try modifying the PP, it is recommended to go through this table first. The client's real concern is often not performance, but 'do I need to change my current molds and processes?'
| Items to move | What needs to be confirmed | What will happen if I don't do it? |
|---|
| Mold shrinkage rate | The difference in shrinkage rate of the new material compared to the original plan is particularly sensitive in long parts | The dimensions are out of tolerance, and the assembly gaps do not align. |
| Gate and Vent | Flame-retardant fillers are more sensitive to gate positions and venting | Underfill, burn marks, weak weld lines |
| Material Temperature and Mold Temperature | The thermal stability windows of halogen-free flame retardant systems are different | Decomposition, surface defects, insufficient weld line strength |
| Dry | It depends on the specific system; flame retardant fillers should be confirmed as needed. | Silver threads, bubbles, performance fluctuations |
| Pressure Holding and Demolding | Shrinkage differences cause deformation and surface whitening | Deformation, extrusion strain |
| Color difference | Outdoor parts must confirm the color board before going on the machine. | Batch color difference and fading disputes |
| Verification order | Sample → Weathering/Hot Wire → Short Shot → Assembly Compliance | All the risks are concentrated to explode at the final step |
Text version conclusion: Changing materials involves three aspects: molds, processes, and color differences, among which the verification sequence should be discussed first. Skipping the small sample and directly testing the mold is equivalent to spending the cost in advance; skipping weather resistance/burning wire tests and going straight to mass production means that a single failure results in the loss of the entire batch, and problems with outdoor parts often take one or two years to become apparent.
9. One-page report sheet (can be directly pasted into PPT)
| Scene | Recommended Route | Key indicators | Verification Standard | Conditions that need to be confirmed first |
|---|
| Outdoor fixed charging pile enclosure | Weather-resistant, halogen-free flame-retardant dual system, glass fiber/mineral filled | ΔE≤3.0; 850°C glowing wire 30 s does not ignite; halogen-free standard | GB/T 16422.2; IEC 60695; Halogen Test | Installation environment (indoor/outdoor), local minimum temperature |
| High flame-retardant demand pile | Halogen-free flame-retardant reinforced PP (glass fiber) | UL94 V-0; GWIT 750/775°C; GWFI 850/960°C | UL94; IEC 60695-2-13/2-12 | Internal electrical density, heat dissipation conditions |
| Long-life outdoor components | Dual-system combined aging verification | UV heat aging 500-1000 h without performance degradation | Outdoor component additional combined aging | Design service life, color depth |
| Cost-sensitive small pile | Weathering system Low flame retardant grade (indoor/mask type) | Primarily weather-resistant, flame-retardant according to components | GB/T 16422.2 | Whether it is indoor, whether it is live intensive |
Text version conclusion: The purpose of this table is to allow technicians to report conclusions directly without having to reorganize their wording. There is only one criterion for judgment—whether the client can use this table to finalize the direction of the materials in a single meeting.
10. The part of this item that is most prone to problems is often not the material.
The most common early failures of this type of component in the industry are outdoor cracking from sun exposure and 'V-0 passed, but the whole device fails safety regulations.' Public information explains the difficulties clearly: the weather resistance of outdoor parts cannot be judged solely by xenon lamp color difference—it also has to maintain performance after 500-1000 hours of UV thermal aging; meanwhile, the inside of a charging pile is electrically dense, and close to real conditions, it must withstand contact with an 850°C wire for 30 seconds without igniting, not just a simple V-0 report.
At the criterion level, the common industry hard lines are as follows: Xenon lamp aging ΔE ≤ 3.0 (GB/T 16422.2); halogen-free quantification: bromine < 900 ppm, chlorine < 900 ppm, total of both < 1500 ppm; glow-wire tests GWIT 750/775℃, GWFI 850/960℃. At the same time, the halogen-free route must avoid the costs associated with halogens — heat during processing releases hydrogen halides that corrode equipment molds, and burning releases hydrogen halides along with dense smoke.
The common practice in the industry is to design the weather-resistant system and the halogen-free flame-retardant system together: for the substrate, choose impact-resistant copolymer PP as the base; for weather resistance, use UVA and HALS additives; for flame retardancy, use halogen-free intumescent type and introduce flake fillers to suppress dripping and control shrinkage; rigidity is restored by mineral or glass fiber fillers — adding them separately is easiest because it's often fine individually but not when combined.
Ningbo Cologne New Materials Co., Ltd. commonly supplies modified polypropylene (PP) pellets in this area, focusing on weather-resistant, halogen-free flame-retardant dual-system types. According to outdoor conditions, they provide corresponding substrate grades and flame-retardant/weather-resistant systems, mainly to address the previously mentioned issues of "cracking under outdoor sunlight and failing the burn test." They can cooperate to make small samples for comparison and mold testing, and can also accommodate multi-variety, small-batch demands from component-level customers.
Frequently Asked Questions
Question: What's the difference between halogen-free and halogen-containing, and why is halogen-free recommended?
Answer: Without naming specific brands, let's discuss verifiable aspects. The quantitative threshold for halogen-free is bromine and chlorine each <900 ppm, total <1500 ppm; the cost of halogenated materials is that processing under heat releases hydrogen halides that corrode equipment molds, and burning releases hydrogen halides and dense smoke. For outdoor live components, halogen-free is a safer option in terms of environmental protection and safety regulations.
Q: If too much flame retardant is added and the mechanical properties drop, can it be compensated by the formula?
Answer: This is a structural issue of PP, not a formulation-level problem. The correct approach is to restore rigidity through mineral or glass fiber filling, while designing both weather resistance and flame retardant systems together, rather than gambling on using less flame retardant. Allowing a slight compromise on any one aspect is more important than choosing the grade first.
| Operating condition | Key criterion | Cologne regular supply |
|---|
| Outdoor charging pile casing | ΔE≤3.0; 850℃ glowing wire 30 s; halogen-free compliant | Weather-resistant, halogen-free flame-retardant dual-system modified PP orientation |
| High flame-retardant pile | UL94 V-0; GWIT/GWFI | Halogen-free flame-retardant reinforced PP (glass fiber) direction |
| Long-life outdoor components | UV thermal aging 500-1000 h without degradation | Dual-System Joint Aging Verification Direction |
Just a reminder: when something goes wrong with an item, the most common mistake is to replace the material first. Cracking in the sun, fading, failing safety standards—each of these issues has more than one cause. First identify the cause, then replace the material; if the order is reversed, you often end up replacing material several times and still get nowhere.
Finally, three last points. First, the first sentence in selecting the casing for a charging pile should be 'Which of the four aspects can be compromised first?' rather than 'Which material is better'—outdoor weather resistance, UV resistance, V-0 flame retardancy, and high strength; all four need to be satisfied simultaneously. Second, the 850°C glowing wire test and UV thermal aging for 500-1000 hours are the two items most easily overlooked in this selection; the former aligns with internal electrical conditions, the latter with outdoor lifespan, both are more relevant to real-world situations than just checking V-0 rating or xenon light color change. Third, the sequence of validation is more important than the individual validation items: prototype → weathering/glowing wire → short-term shooting → assembly compliance, with the glowing wire and aging steps definitely needing to be done before mold trials.
The next article discusses spray-free and scratch-resistant coatings — the thing that is most concerning is not insufficient rigidity, but that the exterior parts first chalk and turn white when exposed outdoors.
About Us
Let's talk about three things before quoting: where this part will be used, which requirements it has, and which requirement can be dropped.
Especially the third point. The indicators of modified PP are not additive; they are trade-offs—flame retardancy versus toughness, high flow versus impact resistance, glass fiber versus dimensional stability. Without ranking them, the price cannot be accurately quoted, and the plan cannot be stabilized.
